The present invention relates to a centrifugal lubricant pick-up tube of the type suitable for use in hermetic motor compressors, and in particular to such a tube which is capable of being snap fit into the compressor shaft so as to facilitate assembly.
In hermetic motor compressors, which are sealed units, the bearing regions are often lubricated by means of a lubricant pick-up tube, which is rotated about its longitudinal axis and has one end immersed in the compressor lubricant sump. The tube is mounted on the shaft of the compressor and exerts a centrifugal pumping action on the lubricant which flows through the lower open end of the tube. The tube propels the lubricant upwardly by means of centrifugal action to passageways in the shaft, which leads to the bearing regions of the compressor. Such pick-up tubes are disclosed, for example, in U.S. Pat. Nos. 3,451,615, 3,410,478 and 4,079,185.
In the past, such pick-up tubes have often been made of deep draw quality cold rolled steel, wherein sheet steel is die blanked into a circular disc and then progressively drawn first into a cup shape and then, in subsequent draws, into an elongated, generally cylindrical tube of uniform diameter. The final shape for the tube is accomplished by subsequent forming operations, including drawing, swaging, and piercing. The tube may be provided with a copper flash finish, if desired. The tube is then removably or permanently press-fit in the compressor shaft.
The obvious disadvantage to such a pick-up tube lies in the number of operations which are necessary to form it. Furthermore, the operation of assembling it to the compressor shaft by a press fit requires the use of special machinery.